Toner cartridge

ABSTRACT

A detachable toner cartridge for use in an electrophotographic printer includes an outer cylinder and an inner cylinder contacting each other and having respective toner discharge outlets that can be overlapped with each other by turning the inner cylinder relative to the outer cylinder so as to discharge toner. The inner cylinder is pressed against the outer cylinder in the circumferential direction to bring the cylinders into close contact to prevent toner leakage. The toner cartridge does not require so high accuracy in manufacturing thereof.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a toner cartridge for feeding toner toelectrophotographic recorders and the like.

2. Background Technology

Cylindrical toner cartridges have been known as conventional tonercartridges. A cartridge of this type is composed of an outer cylinder,an inner cylinder which rotatively contacts the inner surface of theouter cylinder and a pair of caps attached to opposite ends of the innercylinder. The inner cylinder has an empty space therein to accommodatetoner. A plurality of toner discharge outlets are defined in the sidesurface of the outer cylinder in the longitudinal direction thereof,while a plurality of toner discharge outlets also are defined in theside surface of the inner cylinder. The caps also are in contact withopposite ends of the outer cylinder, one of the caps having a tonerfilling opening which is usually equipped with a pug.

A method of filling toner in the toner cartridge set forth above will bedescribed hereinafter. Firstly, the inner cylinder is rotated or turnedrelative to the outer cylinder so that the toner discharge outlets ofthe inner cylinder will not overlap the toner discharge outlets of theouter cylinder. Then the plug is removed from the toner filling openingand toner is filled into the toner cartridge. Thereafter the plug is putin the toner filling opening.

In order to feed the toner to an electrophotographic recorder using thetoner cartridge which is filled with toner in the manner describedabove, the toner cartridge is attached to the electrophotographicrecorder at a predetermined position thereof with the outer tonerdischarge outlets directed downwardly. Thereafter the inner cylinder isturned by a driving means so as to overlap the inner toner outlets withthe outer toner outlets. As a result, the toner is fed to theelectrophotographic recorder through the aligned and overlapped innerand outer toner discharge outlets.

The toner cartridge set forth above, however, has the followingdisadvantages. It is difficult to manufacture the inner and outercylinders in a manner such that the inner cylinder contacts an innersurface of the outer cylinder and at the same time is rotatable withrespect to the outer cylinder. When the outer diameter of the innercylinder is manufactured to be less than the inner diameter of the outercylinder, a gap is defined between the inner and outer cylinders. Suchgap causes leakage therethrough of the toner. When the outer diameter ofthe inner cylinder is manufactured with high accuracy so as to conformto the inner diameter of the outer cylinder to prevent such leakage ofthe toner, the yield of the operation of manufacturing the innercylinder is decreased, thereby increasing the cost of manufacturing thecartridge.

Previously proposed was a method of providing a cutaway portion at apart of the outer cylinder for facilitating the sliding motion of theinner cylinder when the outer diameter of the inner cylinder ismanufactured to be the same as the inner diameter of the outer cylinder(Japanese Patent Application No. 1-122439). The cutaway portion isformed in the outer cylinder extending axially from opposite endsthereof but at positions where it does not overlap the toner dischargeoutlets of the outer and inner cylinders. Such cutaway portion, however,does not sufficiently reduce sliding friction between the outer andinner cylinders so that the turning of the inner cylinder remainsdifficult.

SUMMARY OF THE INVENTION

The object of the present invention is to solve the problems set forthabove and to provide a toner cartridge which has a high performance andan easily turnable inner cylinder.

Furthermore, it is another object of the present invention to provide atoner cartridge which does not require high accuracy in manufacturingthe outer and inner cylinders thereof.

The toner cartridge according to the present invention is composed of anouter cylinder, an inner cylinder having substantially the same lengthas that of the outer cylinder and caps to cover both opposite ends ofthe cylinders. The outer cylinder has openings at both ends thereof andhas an outer toner discharge outlet extending in the longitudinaldirection thereof. The inner cylinder has an inner discharge outletextending in the longitudinal direction thereof and cap fitting portionsat opposite ends thereof. The caps fit on the cap fitting portions. Theinner cylinder is placed rotatably in contact with the inner surface ofthe outer cylinder, and the openings of the latter substantially conformto the cap fitting portions of the former.

The inner cylinder of the toner cartridge according to the presentinvention is composed of a flexible member and has a partially cutawaycylindrical shape, i.e. a C-shaped cross section. An inner tonerdischarge outlet is defined at a partially cutaway portion of the innercylinder, namely, radially between opposite circumferentially spacedends of the inner cylinder. The circumferentially spaced ends of theinner cylinder are brought into contact with the inner wall surface ofthe outer cylinder by applying pressure thereto in the circumferentialdirection of the inner cylinder.

Consequently, gaps are prevented from occurring between thecircumferentially spaced ends of the inner cylinder and the inner wallsurface of the outer cylinder, thus eliminating leakage therebetween oftoner. Since the inner cylinder is made of flexible member and is formedto be C-shaped in cross section, it is possible to manufacture tonercartridges at a high yield, while preventing formation of gaps betweenthe cylinders or without increasing the rotational load due to thevariations of dimensions of the cylinders.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially cutaway perspective view of a toner cartridgeaccording to a first embodiment of the present invention;

FIG. 2 is a perspective view showing an inner cylinder of the tonercartridge according to the first embodiment;

FIG. 3 is a longitudinal cross section of the toner cartridge accordingto the first embodiment;

FIGS. 4(a) and 4(b) are lateral cross sections of the toner cartridgeshowing operation of the first embodiment;

FIG. 5 is a partial perspective view of a toner cartridge according to asecond embodiment;

FIG. 6 is a partially cutaway perspective view of a toner cartridgeaccording to a third embodiment;

FIG. 7 is a cross-sectional view of FIG. 6 taken along line 7--7therein;

FIG. 8 is a perspective view of a B portion of FIG. 6 omitting an outercylinder;

FIG. 9 is a partially cutaway perspective view of a toner cartridgeaccording to a fourth embodiment;

FIG. 10 is an enlarged view of a C portion of FIG. 9;

FIG. 11 is a partially cutaway perspective view of a toner cartridgeaccording to a fifth embodiment;

FIG. 12 is a view as viewed from the arrows 12--12 of FIG. 11, with acap of FIG. 11 omitted; and

FIG. 13 is a cross-sectional view taken along the line 13--13 of FIG.11.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

A toner cartridge according to the first embodiment of the presentinvention will be described with reference to the partially cutawayperspective view of FIG. 1. The toner cartridge 11, as shown in FIG. 1,comprises an outer cylinder 12, an inner cylinder 13 and end caps 14 and15.

The outer cylinder 12 is composed of a thin plate. Openings 16 and 17are defined at opposite ends of the outer cylinder 12. A plurality ofouter toner discharge openings or outlets 18 are formed radially throughthe outer cylinder 12 and extend in the longitudinal direction thereof.Denoted at 12a is an outer cylinder rib between adjacent outlets 18.

On the other hand, the inner cylinder 13 is composed of a flexible andoutwardly resilient plate that is resiliently bendable in the directionsof the arrows 80 as illustrated in FIG. 2. The inner cylinder 13 has asubstantially C-shaped cross section. The resilience of the innercylinder 13 is used to apply a pressure to the inner cylinder 13radially thereof and around the inner circumference thereof. The innercylinder 13 opposite axially extending circumferential ends 13a and 13bwhich form therebetween a gap serving as an inner toner discharge outlet19. The length of the inner toner discharge outlet 19 in thecircumferential direction is defined to be substantially the same asthat of the outer toner discharge outlets 18 described above.

The inner cylinder 13 has cap fitting portions 20 and 21 at bothlongitudinal ends thereof Furthermore, holes 22a, 22b and 22c aredefined in the cap fitting portion 20 while holes 23a, 23b and 23c aredefined in the cap fitting portion 21. The inner cylinder 13 is turnablyin contact with and pressed against the inner surface of the outercylinder 12 at least at the circumferential ends 13a and 13b thereof.The caps 14 and 15 are fixed to the cap fitting portions 20 and 21 byinserting pawls 24 and 25 protruding from the caps 14 and 15,respectively, into the corresponding holes 22a, 22b, 22c, 23a, 23b and23c respectively as illustrated in FIG. 3. The caps 14 and 15 have seals26 formed of elastic members on the outer circumferences thereof whichclosely contact the inner surface of the outer cylinder 12 so as toprevent toner, not shown, from leaking through the sides of the caps 14and 15. The cap 14 has a toner filling inlet 14a into which fits a plug27.

In order to fill toner into the thus constructed toner cartridge 11, theinner cylinder 13 is turned to a position where the inner tonerdischarge outlet 19 and the outer toner discharge outlets 18 do notoverlap each other in the same manner as employed in the conventionalmethod. The inner cylinder 13 can be turned by turning the caps 14 and15 relative to outer cylinder 12 Thereafter the plug 27 is removed fromthe toner filling inlet 14a, toner is filled into the toner cartridgethrough the toner filling inlet 14a, and then the plug 27 is replaced.

The operation of discharging the toner from the toner cartridge 11 willbe described with reference to the cross sectional views of FIGS. 4(a)and 4(b).

As shown in FIG. 4(a), the inner cylinder 13 is turned to the positionwhere the inner toner discharge outlet 19 of the inner cylinder 13 andthe outer toner discharge outlets 18 of the outer cylinder 12 do notoverlap each other, e.g. the former is turned to extend at 90° relativeto the latter, and then toner 30 is filled into the toner cartridge 11.At this time, the circumferential ends 13a and 13b of the inner cylinder13 are brought into close contact with the inner surface 12b of theouter cylinder 12 so that no gaps are created between thecircumferential ends 13a and 13b of the inner cylinder 13 and the innersurface 12b of the outer cylinder 12, and the toner 30 cannot leaktherebetween. In order to discharge the toner 30 from the tonercartridge 11 filled therein, the inner cylinder 13 is turned relative toouter cylinder 12. Cylinder 13 turns smoothly as it can freely moveradially. As shown in FIG. 4(b), the inner toner discharge outlet 19 andthe outer toner discharge outlets 18 are caused to be substantiallyoverlapped with each other, and the toner 30 is discharged therethrough.

Inasmuch as the inner cylinder 13 of the toner cartridge 11 is formed ofa bent elastic plate which closely contacts the inner surface of thecylinder 12 by its resilience, it need not be manufactured to be of highdimensional accuracy. As a result, the manufacturing cost of cartridge11 is reduced.

Second Embodiment

Although the outer cylinder 12 employed in the first embodiment of thepresent invention does not so include, it is possible to provide theouter cylinder with a cutaway portion such as described in the foregoingBACKGROUND TECHNOLOGY, i.e. as disclosed in Japanese Patent ApplicationNo. 1-122439. FIG. 5 is a partially cutaway perspective view of thetoner cartridge according to the second embodiment incorporating suchfeature.

Thus, a cutaway portion 31 is defined in outer cylinder 12 at a positionwhere portion 31 does not overlap the inner toner discharge outlet 19even when the inner cylinder 13 is turned. In the second embodiment, theinner cylinder 13 also is formed of a bent elastic plate which isradially pressed against the outer cylinder 12 by the resilience ofinner cylinder 13.

Third Embodiment

The third embodiment of the present invention will be described withreference to FIG. 6 to FIG. 8. In such figures, components which are thesame as illustrated in FIG. 1 are denoted by the same numerals.

According to the third embodiment, the outer cylinder 12 has a stopperor abutment member 41 at a position on the inner surface of the outercylinder 12 to be abutted by and to stop the circumferential end 13b ofthe inner cylinder 13. The stopper 41 is provided to stop the innercylinder 13 at a position where the outer toner discharge outlets 18 ofthe outer cylinder 12 and the inner toner discharge outlet 19 of theinner cylinder 13 do not overlap each other. The stopper 41 hassubstantially the same length as that of the inner cylinder 13 in thelongitudinal direction, and has the same thickness as that of the innercylinder 13. Therefore, a toner stirring member, not shown, mayrotatably contact the inner surface of the inner cylinder 13.

Adjacent opposite longitudinal ends of the inner cylinder 13 are formedholes 22a, 22b, 22c, 23a, 23b and 23c that are engaged by pawls 24a,24b, 24c, 25a, 25b and 25c of caps 14 and 15, as in the firstembodiment. Gaps are defined between each circumferential edge of eachsuch hole and the corresponding circumferential edges of the respectivepawls. Thus, the pawls can be moved relative to inner cylinder 13 byabout 6° upon turning of the caps 14 and 15.

The caps 14 and 15 have respective projecting members 42 and 43 fixedlymounted thereon at central portions thereof and extend radiallytherefrom to the outer circumference of inner cylinder 13. Consequently,the caps 14 and 15 are integrally formed both with the pawls and theprojecting members. When, for example, the cap 15 is turned in thedirection of the arrow 90 in FIG. 7, the pawls 25a, 25b and 25c canrotate relative to inner cylinder 13 in the same direction by as much as6° and such turning force also is applied to the projecting member 43.One circumferential end 13a of the inner cylinder 13 contacts theprojecting member 43, and the other end 13b thereof is stopped by thestopper 41. Therefore, such rotation of cap 15 causes member 43 to moveend 13a in such turning direction, but member 43 is allowed to yieldelastically as shown in FIG. 7. That is, when the cap 15 is turned inthe direction of the arrow 90, the pawls 25a, 25b and 25c also turn byabout 6° and the projecting member 43 is moved by about 6° in theturning direction, so as to push the circumferential end 13a of theinner cylinder 13 in the circumferential direction thereof. As a result,the inner cylinder 13 is radially expanded so that it is brought intoeven further close contact with the inner surface of the outer cylinder12. At such state, pins 45 and 46 are inserted through fixing holes (notshown) provided in the outer cylinder 12 and into fixing holes 44provided in the side surface of the cap. Thereby, it is possible tofixedly mount the caps 14 and 15 to the outer cylinder 12.

For feeding toner to an electrophotographic recorder, firstly anoperator moves pins 45 and 46 so that the inner cylinder 13 and the caps14 and 15 can be rotated relative to the outer cylinder 12. Thereafter,the operator installs the toner cartridge 11 in the electrophotographicrecorder (not shown) and turns the caps 14 and 15 in a direction reverseto the arrow 90. Consequently, the pawls integral with the caps 14 and15 turn the inner cylinder 13 due to engagement with edges of the holes.As a result, the inner toner discharge outlet 19 of the inner cylinder13 and the outer toner discharge outlets 18 of the outer cylinder 12 areoverlapped each other, so that the toner is fed therethrough to theelectrophotographic recorder.

According to the third embodiment, the projecting members 42 and 43 areresiliently bendable and push the inner cylinder 13 in thecircumferential direction thereof so that the inner cylinder is movedinto even further close contact with the outer cylinder.

Fourth Embodiment

The fourth embodiment is substantially the same as the third embodiment.FIG. 9 is a partially cutaway perspective view of the toner cartridgeaccording to the fourth embodiment, wherein the same components aredenoted by the same numerals and illustration thereof is partiallyomitted.

The third embodiment employed the pins 45 and 46 to fix the caps 14 and15 to the outer cylinder while the fourth embodiment employs easilydestructible projections. That is, the caps 14 and 15 are equipped onthe outer circumferences thereof with projections 51 and 52. Theprojections 51 and 52 engage in cutaway portion 53 and 54, respectively,provided in ends of the outer cylinder 12 at positions corresponding tothe projections. Furthermore, a groove 55 is provided in the outersurface of the cap 14 so as to facilitate the breaking of the projection51, as illustrated in FIG. 10. Thus, the projection 51 is broken atportion D in FIG. 10, so that the cap becomes rotatable relative to theouter cylinder. In order to feed toner to the electrophotographicrecorder, the operator breaks the projections 51 and 52 to make the capsrotatable, and thereafter carries out the operation of feeding toner inthe same manner as in the third embodiment.

Fifth Embodiment

The toner cartridge according to the fifth embodiment will be describedwith reference to FIG. 11 to FIG. 13. The same components as in FIG. 1are denoted by the same numerals. According to the fifth embodiment,stoppers 61 and 62 are provided integrally with the caps 14 and 15 toextend inwardly of outer cylinder 12 As a result, the inner cylinder 13is held between the stoppers 61 and 62 at the end 13a of the innercylinder and the stopper 41 of the outer cylinder 12 at the other end13b of the inner cylinder. On the other hand, leaf springs 63 and 64 areprovided at the edges of the caps 14 and 15. Leaf spring 63 isdetachably provided so that one end thereof engage an end portion 12c ofthe outer cylinder 12 and the other end thereof engages an edge portion14a of the cap 14. Spring 63 thus can turn the cap 14 in the directionof arrow 95 relative to the outer cylinder 12 as illustrated in FIG. 12.The leaf spring 64 is also disposed in the same manner as the leafspring 63, and turns the cap 15 in the direction of arrow 95 shown inFIG. 13. The stoppers 61 and 62 push the end portion 13a of the innercylinder 13 in the circumferential direction thereof as the caps 14 and15 are turned. Thus the leaf springs 63 and 64 push the end portion 13aof the inner cylinder 13 in the circumferential direction thereof, sothat the inner cylinder 13 is brought into even closer contact with theouter cylinder 12.

In order to feed toner to the electrophotographic recorder, the operatorremoves the leaf springs 63 and 64 so as to make the caps rotatable, andthereafter carries out the toner feeding operation in the same manner asdescribed in the foregoing embodiments.

Inasmuch as the detachable leaf springs are employed in the fifthembodiment, the projection 42 and 43 need not be provided for generatinga pushing force as in the third and fourth embodiments. Thus, thestructure of the toner cartridge can be simplified. The two leaf springs63 and 64 can be of the same shape, which facilitates the assemblingoperation owing to symmetry of the springs.

As described above, the toner cartridge according to the presentinvention is adapted for use in electrophotographic printers orduplicators which employ an LED, a laser beam, etc., as a light sourcefor forming a static latent image, particularly to small and economicalelectrophotographic printers.

We claim:
 1. A toner cartridge comprising:an outer cylinder havingtherethrough a radially opening outer toner discharge outlet; an innertoner receiving cylinder positioned within said outer cylinder forcircumferential rotation relative thereto, said inner cylindercomprising an elastic member having a C-shaped configuration intransverse cross section and having circumferentially spaced first andsecond opposite axially extending ends defining therebetween an innertoner discharge outlet; end caps closing axially opposite ends of saidinner and outer cylinders; connecting means for interlocking said endcaps to said inner cylinder, whereby rotation of said end caps relativeto said outer cylinder results in circumferential rotation of said innercylinder relative to said outer cylinder, thus bringing said inner andouter toner discharge outlets into and out of alignment; and means forurging said inner cylinder radially outwardly into toner sealing contactwith said outer cylinder, said inner cylinder being formed of a bentelastic plate having outward resilience, and said urging meanscomprising said resilience.
 2. A cartridge as claimed in claim 1,wherein said outer cylinder has cut-outs formed in opposite end portionsthereof.
 3. A cartridge as claimed in claim 1, wherein said connectingmeans comprise holes formed in opposite end portions of said innercylinder, and pawls projecting from said end caps into respective saidholes.
 4. A cartridge as claimed in claim 1, further comprising sealspositioned circumferentially around said end caps and contacting aninner surface of said outer cylinder.
 5. A toner cartridge comprising:anouter cylinder having therethrough a radially opening outer tonerdischarge outlet; an inner toner receiving cylinder positioned withinsaid outer cylinder for circumferential rotation relative thereto, saidinner cylinder comprising an elastic member having a C-shapedconfiguration in transverse cross section and having circumferentiallyspaced first and second opposite axially extending ends definingtherebetween an inner toner discharge outlet; end caps closing axiallyopposite ends of said inner and outer cylinders; connecting means forinterlocking said end caps to said inner cylinder, whereby rotation ofsaid end caps relative to said outer cylinder result sin circumferentialrotation of said inner cylinder relative to said outer cylinder, thusbringing said inner and outer toner discharge outlets into and out ofalignment; and means for maintaining a first said axially extending endof said inner cylinder circumferentially fixed relative to said outercylinder, and means for moving said second axially extending end of saidinner cylinder circumferentially relative to said outer cylinder,thereby brining an outer surface of said inner cylinder into tightcontact with an inner surface of said outer cylinder.
 6. A cartridge asclaimed in claim 5, wherein said maintaining means comprises a stopperprojecting inwardly of said inner surface of said outer cylinder to beabutted by said first axially extending end of said inner cylinder.
 7. Acartridge as claimed in claim 6, wherein said moving means comprisemembers projecting axially inwardly from said end caps and abutting saidsecond axially extending end of said inner cylinder.
 8. A cartridge asclaimed in claim 7, wherein said members each have a rigid inner portionintegral with a center of the respective said end cap and an elasticportion extending outwardly form said rigid portion and abutting saidsecond axially extending end of said inner cylinder, and furthercomprising fixing means for maintaining said tight contact between saidouter surface of said inner cylinder and said inner surface of saidouter cylinder.
 9. A cartridge as claimed in claim 8, wherein saidfixing means comprises holes formed in end portions of said outercylinder and in said end caps, and pins extending into said holes andmaintaining said end caps circumferentially fixed relative to said outercylinder.
 10. A cartridge as claimed in claim 8, wherein said fixingmeans comprise grooves formed in end portions of said outer cylinder,and destructible projections extending from said end caps into saidgrooves.
 11. A cartridge as claimed in claim 8, wherein said elasticportion of each said member is bendable circumferentially byapproximately 6° relative to said rigid inner portion.
 12. A cartridgeas claimed in claim 7, wherein said moving means further comprisesspring means operable between said end caps and opposite ends of saidouter cylinder.
 13. A cartridge as claimed in claim 12, wherein saidmembers comprise rigid stoppers.
 14. A cartridge as claimed in claim 12,wherein said spring means comprise leaf springs having first ends actingon respective ends of said outer cylinder and second ends acting onrespective said end caps.
 15. A cartridge as claimed in claim 8, whereinsaid leaf springs are mounted detachably.
 16. A cartridge as claimed inclaim 14, wherein said leaf springs have identical configurations.
 17. Acartridge as claimed in claim 6, wherein said stopper has an axiallength and a thickness equal to those of said inner cylinder.